Fresh guidance on new cannabis products for medicinal use
9 April 2019
A new clinical review led by UCL and University of Bath researchers offers new advice to help patients and doctors considering the use of medicinal cannabis.
Since a policy change in November 2018, specialist doctors registered with the General Medical Council (GMC) have been permitted to prescribe new medicines which derive from cannabis. Yet research into these products has, to date, been limited, creating an ‘information vacuum’ into these medicines, their benefits or harms.
A new review published in the BMJ points to the array of different cannabis-based products and cannabinoids available, and a clear need to educate both patients and clinicians into what these different products do and how they might help.
“There have been leaps and bounds in our scientific knowledge in recent years, which combined with confusing claims about the medicinal uses of these drugs can be potentially perplexing for doctors and patients,” said senior author Dr Michael Bloomfield (UCL Psychiatry).
“We hope that our new guidance is helpful to doctors and patients worldwide. Much more research is needed into this new class of medicine.”
In particular, the review points to important differences between products containing THC (the main psychoactive and intoxicating constituent of cannabis) versus CBD (the non-intoxicating element). Although in certain medicines CBD and THC are combined for clinical benefit, in others these components can work independently, playing different roles in improving certain symptoms.
For example, several studies have found that a combination of THC and CBD can alleviate symptoms of chronic pain, while CBD alone may be effective for treatment-resistant epilepsy. By contrast THC alone may be effective for treating nausea and vomiting caused by chemotherapy. THC and CBD are both ‘cannabinoids’ that act in different ways on the body’s endogenous cannabinoid system.
The cannabis plant produces over 144 different cannabinoids such as THC or CBD. Some medicinal products contain THC and/or CBD derived from the cannabis plant, while others contain synthetically produced cannabinoids. CBD is also available in non-medicinal products such as oils and tinctures.
Lead author, Dr Tom Freeman of the University of Bath’s Addiction and Mental Health Group explained: “In this complex and rapidly evolving field, there are several different cannabis-based and cannabinoid medicinal products. These differ in their THC and CBD content, who can prescribe them, and the conditions they may be used to treat. Here we provide an update for clinicians in advance of forthcoming NICE guidelines.
“A key message is that CBD products widely sold online and in health food shops lack quality standards and should not be treated as medicinal products.”
Research on cannabis was previously restricted because it was listed in Schedule 1, implying that it had no medical value. Cannabis was recently moved to Schedule 2 in the UK.
Dr Freeman added: “Research on unlicensed cannabis products has been limited to date. The rescheduling of cannabis and allocation of dedicated UK research funding will improve the evidence we have to guide clinical decision making.”
Co-author Dr Chandni Hindocha (UCL Clinical Psychopharmacology Unit) said: “Resources must be made available to update and educate clinicians about cannabis and cannabinoid based medicines. We would like to encourage doctors to maintain a compassionate and evidence-based approach when engaging with their patients in this rapidly developing field, in order to provide the best standard of care.”
- Research paper in the BMJ
- Dr Michael Bloomfield's academic profile
- Dr Chandni Hindocha's academic profile
- UCL Psychiatry
- UCL Clinical Psychopharmacology Unit
- Medical cannabis shop in Colorado. Credit: O'Dea, Source: Wikimedia Commons
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